|ACE150 - Soil modelling and numerical analyses
|Jordmodellering och numeriska analyser
| Syllabus adopted 2019-02-15 by Head of Programme (or corresponding)
|Grading: TH - Five, Four, Three, Fail
|Education cycle: Second-cycle
Major subject: Civil and Environmental Engineering
Department: 20 - ARCHITECTURE AND CIVIL ENGINEERING
Teaching language: English
Application code: 27124
Open for exchange students: Yes
Maximum participants: 50
MPSEB STRUCTURAL ENGINEERING AND BUILDING TECHNOLOGY, MSC PROGR, Year 2 (compulsory elective)
MPSEB STRUCTURAL ENGINEERING AND BUILDING TECHNOLOGY, MSC PROGR, Year 1 (compulsory elective)
MPIEE INFRASTRUCTURE AND ENVIRONMENTAL ENGINEERING, MSC PROGR, Year 1 (compulsory elective)
MPIEE INFRASTRUCTURE AND ENVIRONMENTAL ENGINEERING, MSC PROGR, Year 2 (compulsory elective)
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In order to be eligible for a second cycle course the applicant needs to fulfil the general and specific entry requirements of the programme that owns the course. (If the second cycle course is owned by a first cycle programme, second cycle entry requirements apply.)
Exemption from the eligibility requirement:
Applicants enrolled in a programme at Chalmers where the course is included in the study programme are exempted from fulfilling these requirements.
Course specific prerequisites
Recommended Chalmers courses: BOM355 Geotechnics, BOM370/BOM325 Hydrogeology and Geotechnics, ideally also ACE045 Geological and Geotechnical Site Investigation and ACE060 Deep Foundations or similar knowledge.
The aim of the course is to equip future Civil and Structural Engineers with up-to-date knowledge on numerical techniques and methods for advanced numerical analyses as part of geotechnical design. The focus is on concepts related to advanced modelling of soil behaviour and how those are incorporated into constitutive models for geotechnical Finite Element Analyses. The course is a highly recommended prerequisite for the students who plan to do their MSc projects in Rock Engineering or Geotechnical Engineering.
Learning outcomes (after completion of the course the student should be able to)
- apply 2D geotechnical finite element (FE) analyses to geotechnical problems
- understand the role of the constitutive model and numerical analyses in geotechnical design, and how some special features (such as stress initialization, initial state, coupled flow-deformation analyses, non-linear soil models and structural elements) are needed for performing geotechnical finite element analyses;
- distinguish between different constitutive (soil) models, considering both simple and advanced soil models, and thus be able to select an appropriate model for a given geotechnical analysis;
- evaluate appropriate input values for the model parameters of the constitutive models considered, and well as to appreciate the sensitivity of the simulation results to the selected parameter values;
- simplify geotechnical and soil-structure interaction problems to create numerical models with increasing complexity
- perform coupled 2D analyses of typical geotechnical problems (embankments, slopes, foundations, excavations) with geotechnical finite element analyses, considering both Ultimate Limit State (ULS) and Serviceability Limit State (SLS);
- present, study and critically assess the results of geotechnical numerical analyses;
○ Introduction to numerical analyses in geotechnics
○ Geotechnical vs. structural FE analyses
○ Displacement based FE formulation (incl. some discussion of element types and shape functions, as typical for geotechnical FEA)
○ Role of constitutive model in geotechnical FEA
● Simple constitutive models
○ Elastic models (linear elasticity, non-linear elasticity and elastic anisotropy)
○ Principles of elasto-plastic models
○ Mohr Coulomb model and its limitations
○ Other elastic-perfectly plastic models (von Mises, Tresca, Drucker-Prager)
● Special features of geotechnical FE analyses
○ Creation of in situ stresses and pore pressures
○ Drained and undrained analyses (total stress models vs. effective stress models)
○ Controlling non-linear analyses
○ Coupled consolidation analyses
○ Factor of safety with geotechnical FEA
○ Modelling structural elements in geotechnical FEA (walls, foundations, anchors, geotextiles, drains, piles, interface elements etc.)
● Advanced constitutive models
○ Critical state models (MCC, Soft Soil) and Hardening Soil model (HS)
○ Constitutive models for structured soils (NGI-ADP, S-CLAY1S)
○ Rate-dependent constitutive models (Soft Soil Creep, Creep-SCLAY1S)
○ Small strain stiffness models (HSsmall)
○ Selection of the soil model dependent on the problem and materials involved
○ Parameter sensitivity and optimisation
The techniques and methods are firstly taught via lectures, which contain materials and experience that is not available in any textbooks, supported by self-studies. The theories are applied in numerical modelling via supervised course-specific computer tutorials using Plaxis 2D FE code, which have been designed to develop the competencies step-by-step. The final step from theory to real problems is done as part of coursework exercises:
- Early on during the course each student is asked to identify, study, understand and replicate/discuss results of a geotechnical numerical study published in a peer reviewed scientific article (individual assignment). The results are presented in a form of a summary report.
- As a group of 2-3 people, students are asked to perform numerical studies of real geotechnical problems (starting from real soil data) at boundary value level. The analyses use geotechnical finite element code Plaxis 2D by applying the best practice taught in the course. The results are presented both orally, and in the form of reports.
The copies of the lecture notes, made available in the course home page, form a major compendium that the students will be expected to add on via self-study. For additional background reading, reference and self-study, the following books are recommended:
- Lees, A, Geotechnical Finite Element Analysis, ICE Publishing, 2016
- Muir Wood, D. Geotechnical Modelling. Spon Press, 2004 (available in e-book)
- Potts, D. & Zdravkovic L. Finite element analysis in geotechnical engineering- Theory. Thomas Telford,1999.
- Potts, D. & Zdravkovic L. Finite element analysis in geotechnical engineering- Application. Thomas Telford,1999.
- Potts, D., Axelsson K., Grande, L. Schweiger, H. & Long, M. Guidelines for the use of advanced numerical analysis. Thomas Telford, 2002.
- Azizi, F. Applied analysis in geotechnics. E & F. Spon, 2000.
- Muir Wood, D. Soil behaviour and critical state soil mechanics. Cambridge University Press,1990.
Examination including compulsory elements
In order to pass the course, the students need to complete the computer tutorials and to submit satisfactorily the coursework assignments, consisting of individual and group assignments. The final mark is based on the assignment marks (with 60% of the mark is based on group project and 40% based on individual assignment/oral presentation).